Charged particle beam writing apparatus and charged particle beam writing method

ABSTRACT

A charged particle beam writing apparatus includes a storage unit to store each pattern data of plural figure patterns arranged in each of plural small regions made by virtually dividing a writing region of a target workpiece to be written on which resist being coated. The charged particle beam writing apparatus further including an assignment unit to assign each pattern data of each figure pattern to be arranged in each of the plural small regions concerned, and a writing unit to write, for each of plural groups, each figure pattern in each of the plural small regions concerned by using a charged particle beam.

CROSS-REFERENCE TO RELATED APPLICATION

This application is based upon and claims the benefit of priority fromthe prior Japanese Patent Application No. 2011-033303 filed on Feb. 18,2011 in Japan, the entire contents of which are incorporated herein byreference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a charged particle beam writingapparatus and a charged particle beam writing method. For example, thepresent invention relates to a writing method and apparatus thatsuppresses resist heating.

2. Description of Related Art

The microlithography technique which advances microminiaturization ofsemiconductor devices is extremely important as being a unique processwhereby patterns are formed in the semiconductor manufacturing. Inrecent years, with high integration of LSI, the line width (criticaldimension) required for semiconductor device circuits is decreasing yearby year. In order to form a desired circuit pattern on semiconductordevices, a master or “original” pattern (also called a mask or areticle) of high precision is needed. Thus, the electron beam writingtechnique, which intrinsically has excellent resolution, is used forproducing such a highly precise master pattern.

FIG. 17 is a schematic diagram explaining operations of avariable-shaped electron beam (EB) writing apparatus. As shown in thefigure, the variable-shaped electron beam writing apparatus operates asdescribed below. A first aperture plate 410 has a quadrangular opening411 for shaping an electron beam 330. A second aperture plate 420 has avariable-shape opening 421 for shaping the electron beam 330 havingpassed through the opening 411 of the first aperture plate 410 into adesired quadrangular shape. The electron beam 330 emitted from a chargedparticle source 430 and having passed through the opening 411 isdeflected by a deflector to pass through a part of the variable-shapeopening 421 of the second aperture plate 420, and thereby to irradiate atarget workpiece or “sample” 340 placed on a stage which continuouslymoves in one predetermined direction (e.g. X direction) during thewriting. In other words, a quadrangular shape that can pass through boththe opening 411 and the variable-shape opening 421 is used for patternwriting in a writing region of the target workpiece 340 on the stagecontinuously moving in the X direction. This method of forming a givenshape by letting beams pass through both the opening 411 of the firstaperture plate 410 and the variable-shape opening 421 of the secondaperture plate 420 is referred to as a variable shaped beam (VSB)method.

When performing the electron beam writing, the layout where a pluralityof figures are densely arranged or figures are arranged to be overlappedwith each other may be written. The case of slash patterns etc. can becited as an example of the layout where figures are arranged to beoverlapped with each other. By performing overlapping of figures, thenumber of shots can be reduced and the writing time can be shortened.When writing such layout figures as they are without any change, thedose density of the electron beam may be high. Therefore, there occurs aproblem of being greatly affected by resist heating compared with a caseof writing layout figures with sparse density. Thus, there is a problemthat dimension etc. of a figure pattern written with such a high densitymay be varied.

As a method of reducing resist heating, for example, generally adoptedis a multiple writing method of performing writing of patterns whileoverlapping them a plurality of times. As the multiple writing method,there are proposed a method of writing all the internal figure patternsa plurality of times by repeating the first writing and the secondwriting per unit of stripe region which is made by virtually dividing achip region, and a method of writing all the internal figure patterns aplurality of times by alternately repeating the first writing and thesecond writing per unit of subfield in the stripe region (refer to,e.g., Japanese Patent Application Laid-open No. 2008-117871).

According to the multiple writing described above, a required dose isobtained by making one dose small for each figure and overlappinglywriting the same figure a plurality of times. Further, it is alsorequested to overcome the problem by other method.

BRIEF SUMMARY OF THE INVENTION

In accordance with one aspect of the present invention, a chargedparticle beam writing apparatus includes a storage unit configured tostore each pattern data of a plurality of figure patterns arranged ineach of a plurality of small regions made by virtually dividing awriting region of a target workpiece to be written on which resist hasbeen coated, wherein the each pattern data includes an assignmentidentifier, defined for each of the plurality of figure patterns, forassigning the each of the plurality of figure patterns concerned to oneof a plurality of groups, to which one of the plurality of figurepatterns concerned belongs, in one of the plurality of small regions, anassignment unit configured to assign the each pattern data of eachfigure pattern to be arranged in the each of the plurality of smallregions concerned such that writing order is sorted per group of theplurality of groups, and a writing unit configured to write, for each ofthe plurality of groups, the each figure pattern in the each of theplurality of small regions concerned by using a charged particle beam.

In accordance with another aspect of the present invention, a chargedparticle beam writing method includes storing, in a storage device, eachpattern data of a plurality of figure patterns arranged in each of aplurality of small regions made by virtually dividing a writing regionof a target workpiece to be written on which resist has been coated,wherein the each pattern data includes an assignment identifier, definedfor each of the plurality of figure patterns, for assigning the each ofthe plurality of figure patterns concerned to one of a plurality ofgroups, to which one of the plurality of figure patterns concernedbelongs, in one of the plurality of small regions, reading the eachpattern data from the storage device, and assigning the each patterndata of each figure pattern to be arranged in the each of the pluralityof small regions concerned such that writing order is sorted per groupof the plurality of groups, and writing, for each of the plurality ofgroups, the each figure pattern in the each of the plurality of smallregions concerned by using a charged particle beam.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram showing a structure of a writing apparatusaccording to Embodiment 1;

FIG. 2 is a flowchart showing main steps of a writing method accordingto Embodiment 1;

FIG. 3 shows an example of a format of pattern data according toEmbodiment 1;

FIG. 4 is a schematic diagram explaining a writing procedure accordingto Embodiment 1;

FIG. 5 is a schematic diagram explaining an SF layer according toEmbodiment 1;

FIGS. 6A and 6B show an example of assigning a plurality of figurepatterns in an SF to a plurality of SF layers by using attributeinformation according to Embodiment 1;

FIGS. 7A and 7B show another example of assigning a plurality of figurepatterns in an SF to a plurality of SF layers by using attributeinformation according to Embodiment 1;

FIGS. 8A and 8B show another example of assigning a plurality of figurepatterns in an SF to a plurality of SF layers by using attributeinformation according to Embodiment 1;

FIGS. 9A and 9B show an assignment state when changing a precisionparameter by using attribute information according to Embodiment 1 shownin FIGS. 7A and 7B;

FIGS. 10A and 10B show an assignment state when changing a precisionparameter by using attribute information according to Embodiment 1 shownin FIGS. 8A and 8B;

FIGS. 11A to 11E show an example of a writing order according toEmbodiment 1;

FIG. 12 is a schematic diagram showing a structure of a writingapparatus according to Embodiment 2;

FIG. 13 is a flowchart showing main steps of a writing method accordingto Embodiment 2;

FIGS. 14A and 14B show an example of writing a plurality of figurepatterns in an SF by using attribute information according to Embodiment2;

FIG. 15 shows an example of a pattern data file according to Embodiment2;

FIG. 16 shows another example of the pattern data file according toEmbodiment 2; and

FIG. 17 is a schematic diagram explaining operations of avariable-shaped electron beam writing apparatus.

DETAILED DESCRIPTION OF THE INVENTION

In the following Embodiments, there will be described a structure inwhich an electron beam is used as an example of a charged particle beam.However, the charged particle beam is not limited to the electron beam,and other charged particle beam, such as an ion beam, may also be used.Moreover, a variable-shaped electron beam writing apparatus will bedescribed as an example of a charged particle beam apparatus.

In the following Embodiments, there will be described a writingapparatus and a writing method that reduce effects due to resistheating.

Embodiment 1

FIG. 1 is a schematic diagram showing a structure of a writing or“drawing” apparatus according to Embodiment 1. In FIG. 1, a writingapparatus 100 includes a writing unit 150 and a control unit 160. Thewriting apparatus 100 is an example of a charged particle beam writingapparatus, and especially, an example of a variable-shaped beam writingapparatus. The writing unit 150 includes an electron lens barrel 102 anda writing chamber 103. In the electron lens barrel 102, there arearranged an electron gun assembly 201, an illumination lens 202, a firstaperture plate 203, a projection lens 204, a deflector 205, a secondaperture plate 206, an objective lens 207, a main deflector 208, and asub deflector 209. In the writing chamber 103, there is arranged an XYstage 105, on which a target workpiece 101, such as a mask, serving as awriting target is placed. The target workpiece 101 is, for example, amask for exposure used for manufacturing semiconductor devices, or amask blank on which resist has been coated and no patterns have beenformed.

The control unit 160 includes a control computer unit 110, a memory 112,a control circuit 120, and storage devices 140, 142, and 144, such as amagnetic disk drive. They are mutually connected through a bus (notshown).

In the control computer unit 110, there are arranged a block assignmentunit 50, a subfield (SF) layer number determination unit 52, a layergeneration unit 54, an assignment unit 56, a shot data generation unit58, and a writing processing unit 59. Functions of units such asdescribed above may be configured by hardware such as an electroniccircuit or may be configured by software such as a program executingthese functions. Alternatively, they may be configured by a combinationof hardware and software. Information input/output from/to the unitsdescribed above and information being currently calculated are stored inthe memory 112 each time.

Moreover, in the assignment unit 56, there are arranged acquisitionunits 60 and 62, judgment units 64 and 68, and an assignment processingunit 66. Functions of units such as described above may be configured byhardware such as an electronic circuit or may be configured by softwaresuch as a program executing these functions. Alternatively, they may beconfigured by a combination of hardware and software. Similarly,information input/output from/to the units described above andinformation being currently calculated are stored in the memory 112 eachtime.

FIG. 1 shows a structure necessary for describing Embodiment 1. Otherstructure elements generally necessary for the writing apparatus 100 mayalso be included. For example, a multi-stage deflector namely the twostage deflector of the main deflector 208 and the sub deflector 209 areherein used for position deflection. A multi-stage deflector of three ormore stage deflector may also be used to perform position deflection.

FIG. 2 is a flowchart showing main steps of a writing method accordingto Embodiment 1. In FIG. 2, a series of steps is executed: a patterndata assignment step (S102) to a processing block, an SF layer numberdetermination step (S104), an SF layer generation step (S106), an SFassignment step (S108), a shot data generation step (S140), and awriting step (S142). As internal steps in the SF assignment step (S108),a series of steps is executed: a pattern data in block acquisition step(S110), an attribute information acquisition step (S112), a judgmentstep (S114), an SF assignment step (S116) or (S118), and a judgment step(S120).

FIG. 3 shows an example of a format of pattern data according toEmbodiment 1. In FIG. 3, the figure code, the size, the arrangementposition, and the attribute information of a figure pattern to bewritten are defined in the pattern data. In this case, as an example,information on the arrangement position of a figure pattern is alsodefined in the pattern data. However, it is not limited thereto. Forexample, arrangement position information may be generated as anotherfile, and, instead of it, an identifier to be linked to the arrangementposition information may be defined in the pattern data file.

FIG. 4 is a schematic diagram explaining a writing procedure accordingto Embodiment 1. In the writing apparatus 100, the writing region of thetarget workpiece 101 is virtually divided into a plurality ofstrip-shaped stripe regions 20. FIG. 4 shows the case where one chip iswritten in the writing region 10 of the target workpiece 101, forexample. Needless to say, a plurality of chips may be written in thewriting region 10 of the target workpiece 101. Dividing is performedsuch that the width of the stripe region 20 is to be a width a littlesmaller than a width deflectable by the main deflector 208. When writingto the target workpiece 101, the XY stage 105 is continuously moved inthe x direction, for example. Thus, the electron beam 200 irradiates onestripe region 20 with continuous movement of the stage. The movement ofthe XY stage 105 in the x direction is a continuous movement, forexample, and the shot position of the electron beam 200 issimultaneously moved by the main deflector 208 to follow the stagemovement. By virtue of performing the continuous movement, the writingtime can be shortened. Moreover, it is also preferable to furthershorten the writing time by moving the XY stage 105 in a variable speed,such as moving in a writable relatively slow speed with respect to apattern dense region, and moving in a relatively fast speed with respectto a pattern sparse region. After writing one of the stripe regions 20,the XY stage 105 is moved in the y direction by step feeding and thewriting operation is performed in the x direction (e.g., reversedirection, this time) for the next one of the stripe regions 20. Byperforming the writing operation in a zigzag manner respectively foreach stripe region 20, the movement time of the XY stage 105 can beshortened.

FIG. 5 is a schematic diagram explaining an SF layer according toEmbodiment 1. When writing each stripe region 20, the writing region ofthe target workpiece 101 is virtually divided into a plurality ofmesh-like subfield (SF) regions 30, and the writing is performed foreach SF. Dividing is performed such that the width of the SF region 30is to be a width a little smaller than a width deflectable by thesubdeflector 209. The SF region is a minimum deflection region in theregions written by the writing apparatus 100.

FIGS. 6A and 6B show an example of assigning a plurality of figurepatterns in an SF to a plurality of SF layers by using attributeinformation according to Embodiment 1. FIG. 6A shows a layout structurewhere a plurality of figure patterns 42 each represented by “A” and aplurality of figure patterns 44 each represented by “B” are denselyarranged in one SFn. When writing, first, the main deflector 208deflects the electron beam 200 to the reference position of the SFregion to be written. Then, the subdeflector 209 emits a shaped beam pershot to the writing position of each figure pattern in the SF. A figurepattern is written by the procedure of changing the position and thebeam shape of each shot and combining the shape of each shot. In thatcase, it is assumed that a plurality of figure patterns 42 and 44 aredensely arranged in one SFn (the n-th SF is herein denoted as SFn) asshown in FIG. 6A. If these densely arranged plural figure patterns 42and 44 are written continuously, the dose density becomes high, and thusthe dimension of written patterns may be changed by the resist heating.

Then, according to Embodiment 1, as shown in FIG. 6B, a plurality oflayers are provided for an SF region, and a plurality of figure patternsarranged in one SF region are distributed to a plurality of SF layers.In the example of FIG. 6B, a plurality of figure patterns 42 eachrepresented by “A” are distributed to the SF concerned of the first SFlayer that is represented as SF_(n-1). A plurality of figure patterns 44each represented by “B” are distributed to the SF concerned of thesecond SF layer, that is represented by SF_(n-2). When distributing,what is necessary is to determine to which SF layer the distribution issent so that the dose density when written may not be too high. In thatcase, to which SF layer a figure pattern is to be assigned may bedefined as attribute information of the pattern data. In the example ofFIG. 6, in the pattern data of the figure pattern 42, the identifier “1”indicating that the figure pattern is to be assigned to the first SFlayer is defined as attribute information. In the pattern data of thefigure pattern 44, the identifier “2” indicating that the figure patternis to be assigned to the second SF layer is defined as attributeinformation. When assigning a figure pattern to an SF, it is possible,by judging the attribute information, to know which SF concerned of SFlayer the figure pattern is to be assigned to.

As described above, when writing a layout where a plurality of figuresare densely arranged or figures are arranged to be overlapped with eachother in the same SF, it is possible, by preparing an SF concerned as aplurality of SF layers and assigning a plurality of figures to one ofthe plurality of SF layers, to make the density of each SF layerapproximately sparse. In other words, it is possible to make the dosedensity per SF layer lower than the original state. Therefore, withrespect to each SF, time has passed since an SF in the first SF layerhas been written until the SF concerned in the second SF layer iswritten, and thereby releasing heat accumulated during the passing timein the resist. Accordingly, pattern dimension variation due to theresist heating can be avoided.

In the case described above, an assignment identifier indicating the SFlayer to which a figure pattern is to be assigned is defined asattribute information. It is also preferable that a precision levelidentifier indicating a required precision level of a figure patternconcerned is also defined in each pattern data.

FIGS. 7A and 7B show another example of assigning a plurality of figurepatterns in an SF to a plurality of SF layers by using attributeinformation according to Embodiment 1. FIG. 7A shows the case of anidentifier of two digits “x and y”, for example, is defined as attributeinformation. For example, the identifier represented by “y” of the firstdigit indicates an assignment identifier of the SF layer describedabove. In other word, a first digit of the attribute informationindicates one of a plurality of SF layers in which a plurality of SFregions are respectively arranged. The identifier represented by “x” ofthe second digit indicates a precision level of the figure patternconcerned. For example, attribute information “11” indicates a figurepattern which is to be assigned to the first SF layer and whoseprecision level is “1”. Attribute information “12” indicates a figurepattern which is to be assigned to the second SF layer and whoseprecision level is “1”. Attribute information “21” indicates a figurepattern which is to be assigned to the first SF layer and whoseprecision level is “2”. Attribute information “22” indicates a figurepattern which is to be assigned to the second SF layer and whoseprecision level is “2”.

FIG. 7A shows the case where three figure patterns 1, 2, and 3 arearranged in an SF60 (SF1), and it is assumed that a part of these threefigure patterns are overlapped with each other. If they are written asthey are, the dose density at the overlapping position will become high,and dimension variation will occur due to resist heating. Therefore, ashas been described in the above example, figure patterns are assigned toa plurality of SF layers so that overlapping of the figures may becleared, thereby aiming to avoid resist heating effect. However, if thenumber of the SF layers increases, the writing time will increaseconsequently. There are some patterns in which dimension variation maybeallowed depending on the precision level required for the figurepattern. Then, such figure patterns are written as they are withoutperforming assignment to a plurality of SF layers. Thereby, the increaseof the writing time can be inhibited. According to Embodiment 1, whetherfigure patterns are assigned to a plurality of SF layers or not isdetermined by comparing the precision parameter previously stored in thestorage device 142 with a precision level identifier (attribute level)defined in each pattern data. Specifically, distribution to a pluralityof SF layers is performed only for the pattern data whose precisionlevel indicated by the precision level identifier defined in eachpattern data is lower than or equal to the precision parameter which hasbeen input and set in the writing apparatus 100.

FIG. 7A shows the assumption that the attribute information of a figurepattern 1(a) is “21”, that of a figure pattern 2(b) is “22”, and that ofa figure pattern 3(c) is “21. In addition, FIG. 7A shows the case theprecision parameter which has been input and set in the writingapparatus 100 is “2”. Since the value of the second digit of eachattribute information of the three figure patterns 1, 2, and 3 arrangedin the SF60 is “2”, it corresponds to the case being lower than or equalto the precision parameter. Therefore, it is judged that the threefigure patterns 1, 2, and 3 can be distributed to a plurality of SFlayers. Then, as shown in FIG. 7B, since the value of the first digit ofeach attribute information of the figure pattern 1 represented by “a”and the figure pattern 3 represented by “c” is “1”, they are distributedto the first layer SF62 (SF₁₋₁). On the other hand, since the value ofthe first digit of the attribute information of the figure pattern 2represented by “b” is “2”, it is distributed to the second layer SF64(SF₁₋₂).

FIGS. 8A and 8B show another example of assigning a plurality of figurepatterns in an SF to a plurality of SF layers by using attributeinformation according to Embodiment 1. FIG. 8A shows the case wherethree figure patterns 4, 5, and 6 are arranged in an SF70 (SF2), and itis assumed that a part of these three figure patterns are overlappedwith each other.

FIG. 8A shows the assumption that the attribute information of a figurepattern 4(d) is “11”, that of a figure pattern 5(e) is “12”, and that ofa figure pattern 6(f) is “11”. In addition, FIG. 8 shows the case theprecision parameter which has been input and set in the writingapparatus 100 is “2”. Since the value of the second digit of eachattribute information of the three figure patterns 4, 5, and 6 arrangedin the SF70 is “1”, it corresponds to the case being lower than or equalto the precision parameter. Therefore, it is judged that each of thethree figure patterns 4, 5, and 6 can be distributed to a plurality ofSF layers. Then, as shown in FIG. 8B, since the value of the first digitof each attribute information of the figure pattern 4 represented by “d”and the figure pattern 6 represented by “f” is “1”, they are distributedto the first layer SF72 (SF₂₋₁). On the other hand, since the value ofthe first digit of the attribute information of the figure pattern 5represented by “e” is “2”, it is distributed to the second layer SF74(SF₂₋₂).

Here, for example, if it is assumed that the precision parameter whichhas been input and set in the writing apparatus 100 is “1”, it willchange as follows:

FIGS. 9A and 9B show an assignment state in the case of changing theprecision parameter by using the attribute information according toEmbodiment 1 shown in FIGS. 7A and 7B. Similarly to the case of FIG. 7A,three figure patterns 1, 2, and 3 are arranged in the SF60 (SF1), and itis assumed that a part of these three figure patterns are overlappedwith each other. It is assumed in the example of FIG. 9A, similarly tothe case of FIG. 7A, that the attribute information of the figurepattern 1(a) is “21”, that of the figure pattern 2(b) is “22”, and thatof the figure pattern 3(c) is “21”. Since the value of the second digitof each attribute information of the three figure patterns 1, 2, and 3arranged in the SF60 is “2”, it does not correspond to the case beinglower than or equal to the precision parameter. Therefore, it is judgedthat any of the three figure patterns 1, 2, and 3 is not able to bedistributed to the plurality of SF layers. In that case, as shown inFIG. 9B, all of the three figure patterns 1, 2, and 3 are distributed tothe first SF layer SF62 (SF₁₋₁).

FIGS. 10A and 10B show an assignment state in the case of changing theprecision parameter by using the attribute information according toEmbodiment 1 shown in FIGS. 8A and 8B. Similarly to the case of FIG. 8A,three figure patterns 4, 5, and 6 are arranged in the SF70 (SF2), and itis assumed that a part of these three figure patterns are overlappedwith each other. It is assumed in the example of FIG. 10A, similarly tothe case of FIG. 8A, that the attribute information of the figurepattern 4(d) is “12”, that of the figure pattern 6(f) is “11”, and thatof the figure pattern 5(e) is “11”. Since the value of the second digitof each attribute information of all the three figure patterns 4, 5, and6 arranged in the SF70 is “1”, it corresponds to the case being lowerthan or equal to the precision parameter. Therefore, it is judged thatall of the three figure patterns 4, 5, and 6 are able to be distributedto a plurality of SF layers. Then, as shown in FIG. 10B, the value ofthe first digit of each attribute information of the figure pattern 4represented by “d” and the figure pattern 6 represented by “f” is “1”,they are able to be distributed to the first layer SF72 (SF₂₋₁). On theother hand, since the value of the first digit of the attributeinformation of the figure pattern 5 represented by “e” is “2”, it isdistributed to the second layer SF74 (SF2-2).

By virtue of the structure described above in which whether an SF layeris to be divided or not is determined according to the precisionparameter and the precision level of each pattern data, it is possibleonly with respect to figure patterns which are required to have highdimension accuracy to avoid pattern dimension variation caused by resistheating, by distributing the figure patterns to a plurality of SFlayers. On the other hand, figure patterns not required to have highdimension accuracy are not deliberately assigned to a plurality of SFlayers in order to be continuously written in the same layer, therebyinhibiting the increase of the writing time. Although the case where theprecision level of each pattern data is “1” or “2” has been describedabove, it is not limited thereto, and it may be a value “3” or more.Similarly, although the case where the value of the precision parameteris “1” or “2” has been described above, it is not limited thereto, andit may be a value “3” or more. What is necessary is to performdetermining based on whether the precision level of each pattern data islower than or equal to the precision parameter or not. Although the casewhere the smaller the value of the precision level of each pattern is,the higher the precision is required has been described, it is notlimited thereto. On the contrary, if it is set that the larger the valueof the precision level of each pattern is, the higher the precision isrequired, the determining can be performed based on whether theprecision level of each pattern data is greater than or equal to theprecision parameter or not.

In the examples of FIGS. 6A-10B, since the first digit of attributeinformation is “1” or “2”, namely two layers, consequently, two SFlayers are generated. Then, first, in order to configure the second SFlayer, the writing region 10 is virtually divided into a plurality ofstripe regions 22 of the second layer as shown in FIG. 4. Then, as shownin FIG. 5, each stripe region 20 of the first layer is virtually dividedinto a plurality of SF regions 30. The first SF layer is configured bythe plurality of these SF regions 30. Similarly, each stripe region 22of the second layer is virtually divided into a plurality of SF regions40. Then, the second SF layer is configured by the plurality of these SFregions 40. FIG. 5 shows the case where the first SF layer and thesecond SF layer are arranged mutually shifted by c1 smaller than the SFsize in the y direction and by c2 smaller than the SF size in the xdirection. For example, they are mutually shifted by ½ of the SF size inthe x and y directions. By shifting, combination precision of thepattern can be improved between stripe regions and between SFs in thestripe region. Moreover, h which is the division width (division height)in the y direction of the stripe regions 20 and 22 is configured to besmaller than the main deflection width D deflectable by the maindeflector 208. Here, both the shifted stripe region 20 and stripe region22 are arranged to be within the deflectable region. That is, it isconfigured to be D≧h+c1. By controlling to have such a dimension, itbecomes possible to write both the stripe region 20 and the striperegion 22 while continuously moving the XY stage 105 in the x direction.In other words, even if the XY stage 105 is not returned, both thestripe regions 20 and 22 can be written by a run corresponding toone-time writing.

Hereafter, the writing method performed in the writing apparatus 100according to Embodiment 1 will be described in order of steps.

First, layout data (writing data) is input from outside the apparatusinto the storage device 140 (an example of a storage unit) to be stored.In the layout data, there is defined each pattern data of a plurality offigure patterns to be arranged in each small region of a plurality ofsmall regions made by virtually dividing the writing region of thetarget workpiece to be written on which resist has been coated.Moreover, in each pattern data, there is defined for each figure patternan assignment identifier to assign a figure pattern concerned to one ofa plurality of SF layers (an example of a plurality of groups) in the SF(small region) to which the figure pattern concerned belongs. In thiscase, the assignment identifier is added as attribute informationdescribed above. Each of these pattern data is stored in the storagedevice 140. Moreover, for example, information on a precision parameteris input from outside the apparatus into the storage device 142 to bestored. However, when the precision level identifier is not defined asthe attribute information for each pattern data, the information on theprecision parameter is not necessarily needed. Each structure operatesas described below under the control of the writing processing unit 59.

In the pattern data assignment step (S102) to a processing block, theblock assignment unit 50 virtually divides the stripe region 20 into aplurality of data processing blocks, and assigns pattern data concernedto each processing block. Data processing is performed, in eachprocessing block, for pattern data of a figure pattern arranged in theprocessing block concerned. Each stripe region 20 is divided into aplurality of processing blocks, and it is preferable to perform dataprocessing in parallel for the plurality of processing blocks, accordingto the number of CPUs, etc. installed in the control computer 110.Hereinafter, in Embodiment 1, pattern data processing in one processingblock will be described.

In the SF layer number determination step (S104), the SF layer numberdetermination unit 52 reads attribute information of each pattern datain the processing block concerned, and determines the number of SFlayers needed. In the example of FIGS. 6 to 10, since the first digit ofthe attribute information is “1” or “2”, the number of SF layers isdetermined to be two layers. In the case that a precision levelidentifier is defined as attribute information in each pattern data, theSF layer number determination unit 52 needs to read the precisionparameter from the storage device 142, and to determine the number of SFlayers, according to the value of the first digit of the attributeinformation, only for the pattern data whose precision level of thesecond digit of the attribute information is lower than or equal to theprecision parameter. Specifically, if the cases shown in FIGS. 9 and 10are mixed, it is determined to be the number of SF layers of FIG. 10because the number is larger than that of FIG. 9.

In the SF layer generation step (S106), the layer generation unit 54generates a plurality of SF layers in which a plurality of SFs (smallregions) are respectively arranged. Concretely, the layer generationunit 54 generates SF layers according to a determined SF layer number.In the examples of FIGS. 6 to 10, two SF layers are generated. In theexample of FIG. 5, the first SF layer is configured by a plurality of SFregions 30. Similarly, the second SF layer is configured by a pluralityof SF regions 40.

In the SF assignment step (S108), the assignment unit 56 assigns eachpattern data to each SF (small region) concerned to be arranged in theSF concerned such that writing order is sorted per SF layer (group).Since writing is performed per SF, when writing an SF in the first SFlayer, there is no writing the corresponding SF in the second layer, forexample. Therefore, when assigning pattern data of one group (groupwhose first digit of attribute information is “1”) to SF_(n-1) of thefirst SF layer, and assigning pattern data of the other group (groupwhose first digit of attribute information is “2”) to correspondingSF_(n-2) of the second SF layer, the writing order is sorted per groupat the time of writing. Moreover, the assignment unit 56 judges eachpattern data whether distribution is sent to a group indicated by theassignment identifier or not depending on the precision levelidentifier. Then, as a result of the judgment, when not distributing toa group indicated by the assignment identifier, the pattern dataconcerned is assigned to one of a plurality of groups which is differentfrom the group indicated by the assignment identifier. In other words,pattern data concerned is assigned to an SF in one of the SF layers.Specifically, as internal steps in the SF assignment step (S108), thesteps described below will be performed.

In the pattern data in block acquisition step (S110), the acquisitionunit 60 acquires pattern data assigned to a processing block concerned.

In the attribute information acquisition step (S112), the acquisitionunit 62 refers to and acquires attribute information from each patterndata.

In the judgment step (S114), the judgment unit 64 reads the precisionparameter from the storage device 142, and judges each pattern datawhether the precision level of the attribute information is lower thanor equal to the precision parameter. Alternatively, it judges whether aprecision level identifier exists in the attribute information or not.When the precision level of the attribute information is lower than orequal to the precision parameter, or when there is no precision levelidentifier, it goes to the SF assignment step (S116). When the precisionlevel of the attribute information is not lower than or equal to theprecision parameter, it goes to the SF assignment step (S118).

The assignment processing unit 66 assigns each pattern data to an SF inone of a plurality of SF layers such that each of the SF layers becomesdifferent per group. Specifically, the assignment is performed asfollows:

In the SF assignment step (S116), with respect to pattern data whoseprecision level of the attribute information is lower than or equal tothe precision parameter or pattern data which includes no precisionlevel identifier, the assignment processing unit 66 assigns the patterndata to a corresponding SF in the SF layer indicated by the first digitof the attribute information.

In the SF assignment step (S118), with respect to pattern data whoseprecision level of the attribute information is not lower than or equalto the precision parameter, the assignment processing unit 66 assignsthe pattern data to a corresponding SF in the first SF layer.

In the judgment step (S120), the judgment unit 68 judges whether the SFassignment processing has been completed for all the SFs in theprocessing block or not. If there is an SF for which the SF assignmentprocessing has not been finished, it returns to S110 to repeat from S110to S120 until the SF assignment processing has been completed for allthe SFs in the processing block.

In the shot data generation step (S140), with respect to the patterndata for which the SF assignment processing has been completed, the shotdata generation unit 58 performs data conversion processing of severalsteps and generates shot data unique to the apparatus. For writing afigure pattern by the writing apparatus 100, it is necessary to divideeach figure pattern so as to have the size which can be irradiated byone beam shot. Therefore, the shot data generation unit 58 divides afigure pattern indicated by each pattern data so as to have the sizewhich can be irradiated by one beam shot, in order to generate a shotfigure. Then, shot data is generated for each shot figure. In the shotdata, a figure type, a figure size, an irradiation position, and a doseare defined, for example. The shot data is defined per SF in the SFlayer concerned in order, for each SF layer. The generated shot data istemporarily stored in the storage device 144 one by one.

In the writing step (S142), the writing processing unit 59 controls thecontrol circuit 120 to make the writing unit 150 perform writingprocessing. The control circuit 120 reads shot data from the storagedevice 144 one by one, and controls the writing unit 150 to write eachfigure pattern on a desired position of the target workpiece 101. Thewriting unit 150 writes each figure pattern in the SF concerned pergroup by using the electron beam 200. Writing is performed for eachstripe according to the SF order described below, for example.

FIGS. 11A to 11E show an example of a writing order according toEmbodiment 1. In the example of FIGS. 11A to 11E, with respect to eachstripe, the writing operation is controlled such that writing of thefirst SF layer and writing of the second SF layer are alternatelyrepeated per SF region group composed of a plurality of SF regionsarranged in the direction (y direction) perpendicular to the movingdirection (x direction) of the XY stage 105. According to thecontrolling as shown in FIG. 11A, first, with respect to the firstcolumn of the first SF layer, writing is performed starting from thelower left SF region 30 in the y direction in order. After the entirefirst column of the first SF layer in the target stripe region 20 hasbeen written, next, with respect to the first column of the second SFlayer as shown in FIG. 11B, writing is performed starting from the lowerleft SF region 40 in the y direction in order. Then, after the entirefirst column of the second SF layer in the target stripe region 22 hasbeen written, next, with respect to the second column of the first SFlayer as shown in FIG. 11C, writing is performed starting from the lowerleft SF region 30 in the y direction in order. After the entire secondcolumn of the first SF layer in the target stripe region 20 has beenwritten, next, with respect to the second column of the second SF layeras shown in FIG. 11D, writing is performed starting from the lower leftSF region 40 in the y direction in order. Similarly, one stripe region20 and one stripe region 22 are written as shown in FIG. 11E byalternately repeating the writing of the first SF layer and the secondSF layer per SF column.

While the XY stage 105 is continuously moving in the x direction(predetermined direction), the writing unit 150 alternately repeatswriting the first SF layer and the second SF layer per SF column, usingthe electron beam 200, as shown in FIGS. 11A to 11E. Specifically, itoperates as follows:

The electron beam 200 emitted from the electron gun assembly 201(emission unit) irradiates the entire first aperture plate 203 having aquadrangular, such as a rectangular, opening by the illumination lens202. At this point, the electron beam 200 is shaped to be a quadranglesuch as a rectangle. Then, after having passed through the firstaperture plate 203, the electron beam 200 of a first aperture image isprojected onto the second aperture plate 206 by the projection lens 204.The first aperture image on the second aperture plate 206 isdeflection-controlled by the deflector 205 so as to change the shape andsize of the beam. After having passed through the second aperture plate206, the electron beam 200 of a second aperture image is focused by theobjective lens 207 and deflected by the main deflector 208 and thesub-deflector 209, and reaches a desired position on the targetworkpiece 101 on the XY stage 105 which continuously moves. FIG. 1 showsthe case of using a multi-stage deflection, namely the two stagedeflector of the main and sub deflectors, for the position deflection.In such a case, what is needed is to deflect the electron beam 200 ofthe shot concerned to the reference position of SF, which is made byvirtually dividing the stripe region, by using the main deflector 208while following the stage movement, and to deflect the beam of the shotconcerned to each irradiation position in the SF by using thesub-deflector 209.

When the writing operation progresses in accordance with the writingorder described above, it is possible to continuously write the first SFlayer and the second SF layer by a run corresponding to one-time writingwithout returning the position of the XY stage 105.

As described above, the writing unit 150 writes each figure patternarranged in each SF by process of, after writing a figure patternassigned to an SF concerned in one SF layer, writing a figure patternassigned to a corresponding SF in another SF layer. By virtue of thisstructure, after writing an SF in the first layer, the heat generatedwhen writing the SF in the first layer can be released by the time ofwriting an SF in the second layer. Therefore, pattern dimensionvariation due to resist heating can be suppressed.

Embodiment 2

In Embodiment 1, pattern dimension variation is avoided by dividing anSF into a plurality of SF layers and assigning a plurality of figuresarranged densely or arranged overlappingly to one of the plurality of SFlayers. However, the method of avoiding pattern dimension variation dueto resist heating is not limited thereto. In Embodiment 2, there will beexplained a method of avoiding pattern dimension variation due to resistheating without dividing an SF into a plurality of SF layers.

FIG. 12 is a schematic diagram showing a structure of a writingapparatus according to Embodiment 2. FIG. 12 is the same as FIG. 1except for that the SF layer number determination unit 52, the layergeneration unit 54, and the judgment unit 64 are removed, the judgmentunit 69 is arranged instead of the judgment unit 68, and the assignmentprocessing unit 67 is arranged instead of the assignment processing unit66. Functions, such as the block assignment unit 50, the assignment unit56, the shot data generation unit 58, and the writing processing unit 59may be configured by hardware such as an electronic circuit or may beconfigured by software such as a program executing these functions.Alternatively, they may be configured by a combination of software andhardware. Information input/output from/to the units described above andinformation being currently calculated are stored in the memory 112 eachtime. Functions, such as the acquisition units 60 and 62, the judgmentunit 69, and the assignment processing unit 67 may be configured byhardware such as an electronic circuit or may be configured by softwaresuch as a program executing these functions. Alternatively, they may beconfigured by a combination of software and hardware. Informationinput/output from/to the units described above and information beingcurrently calculated are similarly stored in the memory 112 each time.

FIG. 13 is a flowchart showing main steps of the writing methodaccording to Embodiment 2. In FIG. 13, a series of steps is executed: apattern data assignment step (S102) to a processing block, an SFassignment step (S130), a shot data generation step (S140), and awriting step (S142). In the SF assignment step (S130), a series of stepsis executed as its internal steps: a pattern data in block acquisitionstep (S132), an attribute information acquisition step (S134), an SFassignment step (S136), and a judgment step (S138). Contents that arenot specially explained are the same as those in Embodiment 1.

FIGS. 14A and 14B show an example of writing a plurality of figurepatterns in an SF by using attribute information according to Embodiment2. FIG. 4A shows the case where three figure patterns 1, 2, and 3 arearranged in the SF60 (SF1), and it is assumed that a part of these threefigure patterns are overlapped with each other. If they are written asthey are, the dose density at the overlapping position will become high,and dimension variation will occur due to resist heating. Then,according to Embodiment 2, “z” being an identifier of one digit isdefined as attribute information. For example, the identifierrepresented by “z” is an example of an assignment identifier fordistributing a plurality of figure patterns in an SF to a plurality ofgroups. For example, attribute information “1” indicates that a figurepattern is to be distributed to the first group. Attribute information“2” indicates that a figure pattern is to be distributed to the secondgroup.

FIG. 14A shows the assumption that the attribute information of thefigure pattern 1(a) is “1”, that of the figure pattern 2(b) is “2”, andthat of the figure pattern 3(c) is “1”.

Then, as shown in FIG. 14B, since the value of the attribute informationof the figure pattern 1 represented by “a” and the figure pattern 3represented by “c” is “1”, they are to be distributed to the firstgroup. On the other hand, since the value of the attribute informationof the figure pattern 2 represented by “b” is “2”, it is to bedistributed to the second group. The pattern data of the three figurepatterns 1, 2, and 3 are to be assigned to the same SF60.

First, layout data (writing data) is input from outside the apparatusinto the storage device 140 (an example of a storage unit) to be stored.In the layout data, as described above, there is defined each patterndata of a plurality of figure patterns to be arranged in each SF of aplurality of SFs made by virtually dividing the writing region of thetarget workpiece to be written on which resist has been coated.Moreover, in each pattern data, there is defined for each figure patternan assignment identifier to assign a figure pattern concerned to one ofa plurality of groups in an SF (small region) to which the figurepattern concerned belongs. In this case, the assignment identifier isadded as attribute information described above. Each of these patterndata is stored in the storage device 140. Moreover, information on astandby time for waiting for writing between groups is input from theoutside into the storage device 142 to be stored. The standby time maybe different depending on the pattern data. Therefore, it is acceptablethere is a plurality of information on the standby time.

The contents of the pattern data assignment step (S102) to a processingblock are the same as those of Embodiment 1.

In the SF assignment step (S130), the assignment unit 56 assigns eachpattern data to each SF (small region) concerned to be arranged in theSF concerned such that writing order is sorted per group. The assignmentunit 56 is an example of the assignment processing unit. After patterndata of one group (group whose attribute information is “1”) has beenwritten and the standby time having been set has passed, pattern data ofanother group (group whose attribute information is “2”) is written. Bythis, the writing order is sorted per group at the time of writing. Inthe SF assignment step (S130), the following steps will be specificallyexecuted as its internal steps.

In the pattern data in block acquisition step (S132), the acquisitionunit 60 acquires pattern data assigned to a processing block concerned.

In the attribute information acquisition step (S134), the acquisitionunit 62 refers to and acquires attribute information from each patterndata.

In the SF assignment step (S136), when assigning pattern data of afigure pattern in an SF to each SF, the assignment processing unit 67controls the definition order of pattern data so that the pattern datamay be sorted per group.

FIG. 15 shows an example of a pattern data file according to Embodiment2. First, the assignment processing unit 67 reads data on the standbytime from the storage device 142. The standby time is defined as shownin FIG. 15. Then, the pattern data belonging to a group 1 (first group)is defined in order. Next, NULL data for identifying a boundary betweengroups is defined. Since NULL data represents nothing, it can besubstantially expressed by making a space. Then, pattern data belongingto a group 2 (second group) is defined in order. When there are three ormore groups, what is necessary is to define pattern data of each groupin order through the NULL data. Alternatively, it is also preferable toconfigure a pattern data file as follows:

FIG. 16 shows another example of the pattern data file according toEmbodiment 2. First, the assignment processing unit 67 reads data onstandby time from the storage device 142. Then, the standby time of thegroup 1 (first group) is defined as shown in FIG. 16. Since the group 1does not need standby time, it may be defined as “0”. Next, pattern databelonging to the group 1 is defined in order. Then, the standby time ofthe group 2 (second group) is defined. The standby time read from thestorage device 142 can be defined as a standby time X of the group 2.Then, pattern data belonging to the group 2 is defined in order. Whenthere are three or more groups, what is necessary is to define patterndata of each group in order through the standby time X.

In the judgment step (S138), the judgment unit 69 judges whether the SFassignment processing has been completed for all the SFs in theprocessing block or not. If there is an SF for which the SF assignmentprocessing has not been finished, it returns to S132 to repeat from S132to S138 until the SF assignment processing has been completed for allthe SFs in the processing block.

The shot data generation step (S140) is the same as that ofEmbodiment 1. In the writing step (S142), the writing processing unit 59controls the control circuit 120 to make the writing unit 150 performwriting processing. The control circuit 120 reads shot data from thestorage device 144 one by one, and controls the writing unit 150 towrite each figure pattern on a desired position of the target workpiece101. When writing a pattern in an SF, the writing unit 150 provides astandby time between groups and writes each figure pattern for eachgroup. What is necessary for the standby time is to set it to be a timeperiod for releasing the heat accumulated by the previous group writing.

That is, when the writing unit 150 writes each figure pattern arrangedin each SF, the heat accumulated by the writing of the previous groupcan be released by providing a standby time between groups. Therefore,pattern dimension variation by resist heating can be suppressed.

Referring to specific examples, Embodiments have been described above.However, the present invention is not limited to these examples.

While the apparatus structure, control method, etc. not directlynecessary for explaining the present invention are not described, someor all of them may be suitably selected and used when needed. Forexample, although description of the structure of a control unit forcontrolling the writing apparatus 100 is omitted, it should beunderstood that some or all of the structure of the control unit is tobe selected and used appropriately when necessary.

In addition, any other charged particle beam writing apparatus andmethod thereof that include elements of the present invention and thatcan be appropriately modified by those skilled in the art are includedwithin the scope of the present invention.

Additional advantages and modification will readily occur to thoseskilled in the art. Therefore, the invention in its broader aspects isnot limited to the specific details and representative embodiments shownand described herein. Accordingly, various modifications may be madewithout departing from the spirit or scope of the general inventiveconcept as defined by the appended claims and their equivalents.

1. A charged particle beam writing apparatus comprising: a storage unitconfigured to store each pattern data of a plurality of figure patternsarranged in each of a plurality of small regions made by virtuallydividing a writing region of a target workpiece to be written on whichresist has been coated, wherein the each pattern data includes anassignment identifier, defined for each of the plurality of figurepatterns, for assigning the each of the plurality of figure patternsconcerned to one of a plurality of groups, to which one of the pluralityof figure patterns concerned belongs, in one of the plurality of smallregions; an assignment unit configured to assign the each pattern dataof each figure pattern to be arranged in the each of the plurality ofsmall regions concerned such that writing order is sorted per group ofthe plurality of groups; and a writing unit configured to write, foreach of the plurality of groups, the each figure pattern in the each ofthe plurality of small regions concerned by using a charged particlebeam.
 2. The apparatus according to claim 1, further comprising: a layergeneration unit configured to generate a plurality of layers in whichthe plurality of small regions are respectively arranged, wherein theassignment unit assigns the each pattern data to one of the plurality ofsmall regions in one of the plurality of layers such that each of theplurality of layers is different per group of the plurality of groups,and the writing unit, when writing the each figure pattern arranged inthe each of the plurality of small regions, after writing one of theplurality of figure patterns assigned to one of the plurality of smallregions concerned in one of the plurality of layers, writes another ofthe plurality of figure patterns assigned to the one of the plurality ofsmall regions concerned in another of the plurality of layers.
 3. Theapparatus according to claim 1, wherein the each pattern data furtherincludes a precision level identifier that indicates a necessaryprecision level of one of the plurality of figure patterns concerned,and the assignment unit judges the each pattern data whether the eachpattern data concerned is to be distributed to one of the plurality ofgroups indicated by the assignment identifier, depending on theprecision level identifier, and, as a result of judgment, when notdistributing the pattern data concerned to the one of the plurality ofgroups indicated by the assignment identifier, assigns the pattern dataconcerned to another of the plurality of groups which is different fromthe one of the plurality of groups indicated by the assignmentidentifier.
 4. The apparatus according to claim 1, wherein the writingunit provides standby time between groups of the plurality of groups,and writes each of the plurality of figure patterns for each of theplurality of groups.
 5. The apparatus according to claim 1, wherein theassignment unit further includes an acquisition unit, which isconfigured to acquire pattern data from the storage unit.
 6. Theapparatus according to claim 5, wherein the assignment unit furtherincludes an another acquisition unit, which is configured to acquireattribute information from each acquired pattern data.
 7. The apparatusaccording to claim 6, further comprising: a storage device configured tostore a precision parameter, wherein the attribute information has aprecision level identifier that indicates a necessary precision level,and the assignment unit further includes a judgment unit configured toread the precision parameter from the storage device and judge the eachpattern data whether a precision level of the attribute information islower than or equal to the precision parameter.
 8. The apparatusaccording to claim 7, wherein a first digit of the attribute informationindicates one of a plurality of layers in which the plurality of smallregions are respectively arranged, and the assignment unit furtherincludes an assignment processing unit configured to assign, withrespect to pattern data whose precision level of the attributeinformation is lower than or equal to the precision parameter or patterndata which includes no precision level identifier, the pattern dataconcerned to a corresponding small region of the plurality of smallregions in a layer indicated by a first digit of the attributeinformation.
 9. The apparatus according to claim 8, wherein theassignment processing unit, with respect to pattern data whose precisionlevel of the attribute information is not lower than or equal to theprecision parameter, assigns the pattern data concerned to acorresponding small region of the plurality of small regions in a firstlayer.
 10. The apparatus according to claim 1, further comprising: alayer generation unit configured to generate a plurality of layers inwhich the plurality of small regions are respectively arranged, and astorage device configured to store a precision parameter, wherein theassignment unit assigns the each pattern data to one of the plurality ofsmall regions in one of the plurality of layers such that each of theplurality of layers is different per group of the plurality of groups,and the writing unit, when writing the each figure pattern arranged inthe each of the plurality of small regions, after writing one of theplurality of figure patterns assigned to one of the plurality of smallregions concerned in one of the plurality of layers, writes another ofthe plurality of figure patterns assigned to the one of the plurality ofsmall regions concerned in another of the plurality of layers, whereinthe each pattern data includes attribute information having a precisionlevel identifier that indicates a necessary precision level, a firstdigit of the attribute information indicates one of a plurality oflayers in which the plurality of small regions are respectivelyarranged, and the assignment unit further includes an acquisition unitconfigured to acquire the pattern data from the storage unit, anacquisition unit configured to acquire attribute information from eachacquired pattern data, a judgment unit configured to read the precisionparameter from the storage device, and judge the each pattern datawhether the precision level of the attribute information is lower thanor equal to the precision parameter, and an assignment processing unitconfigured, with respect to pattern data whose precision level of theattribute information is lower than or equal to the precision parameteror pattern data which includes no precision level identifier, to assignthe pattern data concerned to a corresponding small region of theplurality of small regions in a layer indicated by a first digit of theattribute information, wherein the assignment processing unit, withrespect to pattern data whose precision level of the attributeinformation is not lower than or equal to the precision parameter,assigns the pattern data concerned to a corresponding small region ofthe plurality of small regions in a first layer.
 11. The apparatusaccording to claim 1, further comprising: a storage device configured tostore a precision parameter, wherein the each pattern data furtherincludes a precision level identifier that indicates a necessaryprecision level of one of the plurality of figure patterns concerned,and the assignment unit includes an acquisition unit configured toacquire the pattern data from the storage unit, an acquisition unitconfigured to acquire the precision level identifier from each acquiredpattern data, a judgment unit configured to read the precision parameterfrom the storage device, and judge the each pattern data whether theeach pattern data concerned is to be distributed to one of the pluralityof groups indicated by the assignment identifier depending on theprecision level identifier, and an assignment processing unitconfigured, with respect to pattern data distributed to the one of theplurality of groups indicated by the assignment identifier, to assignthe pattern data concerned to the one of the plurality of groupsindicated by the assignment identifier, wherein the assignmentprocessing unit, with respect to pattern data not distributed to the oneof the plurality of groups indicated by the assignment identifier,assigns the pattern data concerned to another of the plurality of groupswhich is different from the one of the plurality of groups indicated bythe assignment identifier, and the writing unit provides standby timebetween groups of the plurality of groups, and writes each of theplurality of figure patterns for each of the plurality of groups.
 12. Acharged particle beam writing method comprising: storing, in a storagedevice, each pattern data of a plurality of figure patterns arranged ineach of a plurality of small regions made by virtually dividing awriting region of a target workpiece to be written on which resist hasbeen coated, wherein the each pattern data includes an assignmentidentifier, defined for each of the plurality of figure patterns, forassigning the each of the plurality of figure patterns concerned to oneof a plurality of groups, to which one of the plurality of figurepatterns concerned belongs, in one of the plurality of small regions;reading the each pattern data from the storage device, and assigning theeach pattern data of each figure pattern to be arranged in the each ofthe plurality of small regions concerned such that writing order issorted per group of the plurality of groups; and writing, for each ofthe plurality of groups, the each figure pattern in the each of theplurality of small regions concerned by using a charged particle beam.